This second engineer has one flaw in his reasoning that the first shares:
In paragraph 2, the Engineer presents the assumption that roughly 10 children out of 35 are "good." Given my personal observations, I conclude that this would lead us to overestimate of the number of Christian households containing at least one "good" child by an order of magnitude at the absolute minimum.
In my personal experience, the antiquated custom of bad children receiving coal in their stockings has been completely overlooked - this function is included in Santa's profile, unless someone else has been subcontracted to complete said task.
In addition, these bad children tend to still wind up with some of the best toys, effectively disproving said custom.
I was a good kid growing up, and I got apples and oranges in my stockings - what's up with that?